Rayville, LA, USA
N744MD
Robinson R44
The 597-hour private pilot was departing on his third flight to the north. Immediately after take-off the helicopter spun to the right and the low rotor rpm warning sounded. The pilot stated "that as soon as the right yaw was felt, left rudder was applied but had no effect". At about 20 feet above the ground, the pilot entered an autorotation. The pilot further stated that, " evidently, I flared too much and the tail boom struck the ground". After the rotor stopped, the pilot and three passengers exited the helicopter. The FAA Rotorcraft Flying Handbook (FAA-H-8083-21), page 11-10, states, "Under certain conditions of high weight, high temperature, or high density altitude, you might get into a situation where the (rotor) rpm is low even though you are using maximum throttle". The handbook continues, " since the tail rotor is geared to the main rotor, low main rotor rpm may prevent the tail rotor from producing enough thrust to maintain directional control". There was no mechanical deficiencies prior to the accident. The NTSB Investigator in Charge calculated the density altitude at 2,033 feet, and the take-off weight to be within 100 pounds of the helicopters maximum certified weight.
On June 19, 2005, approximately 1430 central daylight time, a single-engine Robinson R44 helicopter, N744MD, was substantially damaged during a hard landing following an autorotation near Georgetown, Texas. The private pilot and three passengers were not injured. The helicopter was owned and operated by Drake's Landing Incorporated of Archibald, Louisiana. Visual meteorological conditions prevailed, and a flight plan was not filed for the flight conducted under the provisions of 14 Code of Federal Regulations Part 91. The local flight departed from a private airport, near Rayville, Louisiana, at 1430. The 597-hour pilot reported in the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2) he was departing to the north on his third flight of the day. Immediately after take-off the helicopter spun to the right and the low rotor rpm warning sounded. The pilot stated, "that as soon as the right yaw was felt, left rudder was applied but had no effect". At about 20 feet above the ground, the pilot entered an autorotation. The pilot further stated that, "evidently, I flared too much and the tail boom struck the ground". After the main rotor stopped, the pilot and three passengers exited the helicopter. The pilot reported no mechanical deficiencies prior to the accident. The helicopter came to rest upright on its belly, with the skids spread. The pilot reported damage to the helicopters tail boom, tail rotor blades, and skids. According to the FAA Rotorcraft Flying Handbook (FAA-H-8083-21), page 11-10, states, "Under certain conditions of high weight, high temperature, or high density altitude, you might get into a situation where the (rotor) rpm is low even though you are using maximum throttle". The handbook continues, " since the tail rotor is geared to the main rotor, low main rotor rpm may prevent the tail rotor from producing enough thrust to maintain directional control". At 1453, the automated weather observing system at the Monroe Regional Airport (MLU) near Monroe, Louisiana , located approximately 11 miles northwest of the accident site, reported wind from 020 degrees at 11 knots, gusting to 17 knots, 10 statute miles visibility, scattered clouds at 6,000 feet, temperature 88 degrees Fahrenheit, dew point 57 degrees Fahrenheit, and an altimeter setting of 30.01 inches of Mercury. The NTSB Investigator in Charge calculated the density altitude at 2,033 feet, and the take-off weight to be within 100 pounds of the helicopter's maximum certified weight.
The pilot's loss of control following an encounter with loss of tail rotor effectiveness. A contributing factor was the high density altitude.
Source: NTSB Aviation Accident Database
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